1. Field of the Invention
The present invention relates to a portable telephone and an additional device for the portable telephone connected to the portable telephone.
2. Description of the Related Art
A conventional portable telephone P has a portable telephone main body 10 and a battery 20 detachably attached to the portable telephone main body 10, and the portable telephone main body 10 has, on its bottom, a connector 11 for connecting to an external equipment, as shown In FIGS. 1 to 4.
In the portable telephone P having the above-mentioned constitution, the portable telephone main body 10 operates by a power source fed from the battery 20.
However, in the case that a power source is additionally provided In order to prolong a conversation talk time of the portable telephone main body 10, it is necessary to connect an external power source to the connector 11 for external equipment connection disposed in the portable telephone main body 10.
As shown in FIG. 5, in order to connect an external equipment 40 to the portable telephone P having the above-mentioned constitution, a repeater 60 is required between the portable telephone main body 10 and the external equipment 40. That is, for example, in the case that the portable telephone main body 10 in the portable telephone P is connected to the external equipment 40 as a terminal for computer communication to carry out computer communication, an analog or digital signal is fed from the portable telephone main body 10, in case of analog signal, the repeater 60 is required as a modem in order that a signal format may be converted into a digital signal and then fed to the external equipment 40.
That is, in the case that the conventional portable telephone is additionally provided with a power source, connected to the external equipment, or modified to increase functions, the power source or an additional device such as the repeater for increasing the functionality must be connected to the connector 11 for external equipment connection of the portable telephone main body 10. In consequence, such an additional device is not integral with the portable telephone main body 10, so that the portability of the portable telephone P deteriorates.
In addition, Japanese Patent Application Laid-open No. 99093/1992 discloses a radio equipment which is detachably equipped with a battery pack. In this radio equipment, a lug is formed in the vicinity of the lower end of the radio equipment main body, a locking piece and a knob are disposed on the upper side thereof, and a recess for engaging with the lug of the radio equipment main body is formed in the battery pack to facilitate the detachment of the battery.